含硬涂层结构的表面微观接触新模型

为研究含有硬涂层的粗糙表面中微凸体和基体变形对表面微观接触特性的影响规律,利用Hertz接触理论分别求出微凸体和基体的接触刚度,利用不动点迭代法确定微凸体变形量,建立关于微凸体接触变形量的刚度模型,通过并联关系耦合接触刚度,建立新的接触表面微观接触模型。为验证新模型对含有硬涂层的粗糙表面接触特性描述的正确性,建立了不同大小和不同材料的单微凸体有限元模型,通过与Hertz模型、有限元分析结果比较,发现当基体材料和微凸体材料不同时,微凸体/基体系统的应力分布会不均匀,微凸体表面的接触力比材料相同时的接触力小,最大应力比材料相同时的最大应力大;在变形量很小的时候,Hertz模型解和新模型解都很好地与有限元分析结果相吻合,随着变形量的变大,有限元分析解和新模型解开始同时偏离Hertz模型解,但新模型解一直趋近于有限元分析解。     

食品接触材料中微塑料的释放及检测

目的 讨论微塑料从食品包装、餐具、厨具、加工机械等食品接触材料中的释放途径和检测技术,为食品接触材料中微塑料选择和组合多样化的分析方法提供建议,为食品接触材料中微塑料及相关有毒有害物质的监测研究提供依据。方法 首先概述食品接触材料中微塑料的释放途径及影响因素,其次系统阐述食品接触材料中微塑料的分离富集技术,以及显微镜法、光散射法、光谱法和热裂解气相色谱质谱法等多种检测技术,针对不同技术的适用范围和特点进行比较和分析,并提出具有代表性的食品接触用材料中微塑料从样品处理到颗粒分析的框架和技术路线图,以识别微塑料的化学成分、形貌、丰度、尺寸及分布等特性。结论 针对不同的样品和场景,有必要选择和组合多样化的技术,以达到最优的路径,同时标准化的分析方法和检测技术处理仍是食品接触材料中微塑料风险评估的一大挑战,还亟待提出更为规范的标准化操作流程和检测技术,以提高结果准确性。     

玻璃基底上的蛋白质微接触压印图型化

研究了一种将胶原Ⅰ型蛋白通过微接触压印技术图型化于玻璃基底表面的方法.采用标准光刻工艺制备印章母版,并运用反应离子刻蚀设备对印章表面进行氧等离子体处理,以期改善印章表面亲水性能.将涂敷了胶原Ⅰ型蛋白,并经返潮处理的印章以50 g/cm^2大小的力与玻璃表面接触10 s,得到蛋白质微图型.结果表明,采用反应离子刻蚀技术能显著改善聚二甲基硅氧烷（PDMS）印章表面的亲水性.表面亲水性得到改善的PDMS印章,在经过湿盒返潮后,再进行微接触压印得到的蛋白质微图型其质量得到显著提高.     

新技术、新工艺、新装置

反应合成技术制备银氧化锡电接触材料获得突破2003年11月7日,云南省科技厅主持邀请有关专家对昆明理工大学和昆明贵金属研究所承担的云南省科技攻关项目“银氧化锡电接触复合材料反应合成新技术研究”进行验收鉴定。该项目采用昆明理工大学陈敬超教授等人发明的具有自主知识产权的反应合成技术制备银氧化锡电接触材料、开发可替代银氧化镉材料的银氧化锡产品,其技术特点是:材料制备过程与粉末冶金法相当,材料合成技术与内氧化法相近;原料准备简单、工艺流程短,氧化锡颗粒的弥散随加工过程完成,易于材料的后续加工,生产过程无污染、产品质量…     

切向荷载下弹塑性材料的微观位移特性

Fujimoto(2000)研究了受切向荷载作用的微凸体在完全弹性接触或完全塑性接触条件下的微观位移特性。而实际大多数微凸体在法向荷载作用下,因材料的弹塑性性质导致其接触是很难达到完全弹性接触或完全塑性状态的。因此,如何解决切向荷载作用下处于弹塑性接触状态的微凸体的微观位移特性就显得非常重要。作者以Fujimoto模型为基础,结合Cattaneo和Mindlin理论,研究了切向荷载作用下处于弹塑性接触状态微凸体的摩擦力-微观位移关系,并给出了一个计算实例,显示该文理论模型的合理性。     

宁波材料所在表面高分子功能化技术方面取得进展

图案化高分子薄膜材料在诸如光电子器件及化学和生物芯片等多个领域的应用越来越广泛,因而发展简单、高效且低成本获得图案可调的高分子薄膜新方法具有十分重要的意义。微接触印刷技术因制备工艺简单、成本低廉、无需复杂苛刻的条件,受到学术界、工业界的青睐,被广泛用来织构以表面接枝高分子刷为代表的图案化高分子薄膜材料。该技术通常是利用微接触来转移印章上作为"墨水"的引发剂到目标基底上,经表面引发聚合进行放大而获得表面限定的高分子刷薄膜材料。然而目前微接触印刷技术基本采用巯基引发剂与     

双粗糙滑动表面间接触热导研究

粗糙表面之间的接触热导对机械设备的可靠性和使用寿命具有非常重要的影响。对相对滑动的两个粗糙表面之间的有效接触热导进行了分析和预测,得到了适用于不同Pe数下的接触热导计算公式。研究表明:高Pe数下,滑动粗糙表面间的有效接触热导不仅与接触压强、材料热物性参数以及表面粗糙度有关,而且与滑动速度的平方根成正比;低Pe数或者静态下,材料参数、微凸体峰顶半径一定时,有效接触热导与接触压强成近似线性关系。该研究结果可为表面强化换热提供设计依据。     

构筑生物分子微图案的研究进展

随着微加工技术的发展,在材料表面构筑功能化的纳微米级图案越来越成为关注的热点。在生物科学领域,光刻蚀、微接触印刷和蘸笔纳米平板印刷等微图案技术被广泛应用并实现了生物分子在几十纳米微区域上的固定。生物分子在微纳米区域内的成功固定大大推动了生物微分析、生物芯片、生物微器件等生物技术及相关领域的发展。本文从分析生物分子与材料表面的相互作用入手,较为系统地评述了构筑生物分子微图案的几种重要方法,并对生物分子微图案技术的发展做了展望。     

结合面静态接触参数的统计模型研究

基于对粗糙表面形貌统计分析的基础上,综合考虑微凸体的完全弹性、弹-塑性和完全塑性三种变形机制,建立了结合面的接触面积、接触载荷及接触刚度的统计模型。该模型揭示了结合面接触参数与材料性能参数及粗糙表面形貌参数之间复杂的非线性关系。在不同的微凸体高度随机分布及塑性指数条件下,对接触参数进行预估和对比研究。结果表明,修正的指数分布对高斯分布有着较好的近似,而简单的指数分布与高斯分布之间的误差较大,且相差1至3个数量级;接触表面间距减小时,接触参数值均呈现增大的趋势;塑性指数增大时,接触载荷和接触刚度都随之增大,而接触面积的变化较小。     

硝磷酸腐蚀对CdTe薄膜性能及背接触层的影响

采用硝磷酸(NP)背表面刻蚀工艺并结合真空共蒸发法分别沉积了几种背接触层材料,研究了NP腐蚀对CdTe薄膜性能及背接触层的影响.结果表明:NP腐蚀后在CdTe薄膜上产生了富碲层;退火后,碲容易与背接触材料中的铜反应生成CuxTe.通过严格控制和优化腐蚀工艺,选择ZnTe/ZnTe:Cu作为背接触层材料,可制备出优异性能的CdTe太阳电池.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.     

Evaluation of fatigue life of steel using steel grain size

The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase.